Health briefs.

Ovarian Cancer

More Ovulations May Mean Higher Risk Of Gene Mutation

July 02, 1997|By From Tribune news services.

WASHINGTON — The risk of ovarian cancer is directly related to a woman's lifetime number of ovulations, or menstrual cycles, according to researchers who found that bearing children and birth control pills provide protection from the disease.

A high number of ovulations can increase by nine times the chances of producing cells with a genetic flaw that often leads to ovarian cancer, said Dr. Andrew Berchuck, professor of gynecologic oncology at the Duke University Medical Center.

A statistical link between the number of ovulations and ovarian cancer has been known for some time, but the new study suggests the reason: A high number of ovulations increases the chances a tumor suppressor gene called p53 can be mutated, Berchuck said.

Anything that lowers the number of lifetime ovulation cycles thus reduces the risk of ovarian cancer, Berchuck said.

"If you have one baby, it decreases your risk by about 13 percent," he said. "If you have three babies, your risk is about half that of women who had no babies."

The study also clearly shows that birth control pills, which control ovulation, protect against ovarian cancer, he said. If the pill is taken for a year, it gives a 10 percent protection, while its use for five to 10 years cuts the risk in half. Nursing a newborn also reduces the number of ovulations.

The study will be published Wednesday in the Journal of the National Cancer Institute.